Daniel has exactly $20$ pieces of candy. He has to divide them equally among his $3$ sisters. What is the least number of pieces he should take away so that he could distribute the candy equally?
Explanation: When you divide $20$ by $3$, you get $6$ with a remainder of $2$. Therefore, he should take away $\boxed{2 \text{ pieces}}$ so he could give each of his sisters $6$ pieces.